Termite control is a complicated problem made more difficult by competing societal goals and objectives. Termites are highly mobile, exist in great numbers, and depending on the geography, tend to live in multiple colonies per acre. This coupled with the fact that termites tend to, at least initially, be most active near or under ground level, renders termite detection and control difficult.
In the past, compounds such as chlordan(e) (1, 2, 4, 5, 6, 7, 8, 8-Octachloro-2, 3, 3a, 4, 7, 7a-hexahydro-4, 7-methano-1H-indene) were applied at or near the base of wooden structures. Chlordan(e) provided an efficacious level of protection. However, chlordan(e) tended to migrate into ground water. In addition, regrettably, chlordan(e) was at least somewhat toxic to humans in addition to its relatively high level of termite toxicity. Toxicity in humans resulted in, in mild cases, moderate skin irritation and, in other, more serious situations, irritability, convulsions, deep depression, degenerative liver disease and poisoning. For this reason, the EPA cancelled the registration of chlordan(e) and its use has dwindled, particularly in the United States.
Unfortunately, chlordan(e) was the single most efficacious chemical for controlling termites, and in particular, limiting their damage to structures. Other termiticides or toxicants have followed. However, for one reason or another, none have been able to match chlordan(e)'s efficacy. Some new generation toxicants attempted to overcome chlordan(e)'s problems by binding with organic matter. However, this tends to leave "gaps" in the soil barrier resulting in lower efficacy.
A number of other technologies have also been employed as a substitute for using treatments at or near the base of structures. Principal amongst these is the use of termite baits. Baits are attractants which can be buried just under the surface, throughout a property. The baits should preferentially attract termites to the bait as opposed to a wood structure. Often baits include various termiticides or toxicants which are carried by termites back to their colonies so that both the foraging termites and the non-foraging termites may be killed.
Baits have a number of problems. First, termites are random opportunistic foragers. Therefore, they are almost as likely to attack a wood structure as they are to attack a bait station. Second, there are advantages and disadvantages to making baits strong enough to attract termites. A bait should be strong enough to draw termites away from a building. However, it should not be so strong that termites are attracted from surrounding acreage and unnecessarily brought into the proximity of the building. As will be readily appreciated, a difficult balance must be struck. Finally, baits are exposed to extremes of weather and soil conditions and environmental concerns with regard to the leaching of termiticides as well as efficacy concern with regard to the leaching of the attractant remain ever present.
In addition, a review of the known bait technology demonstrates that baits actually do very little to attract termites. See Pest Control Technology, July 1993, pgs. 72 et seq. In fact, subterranean termites may not be attracted even when they are an inch or less away from the bait. In truth, all a bait can do is provide another source of attack for termites. Of course, because of the presence of the toxicants, termites which happen to attack a bait source will be killed as will other termites back in the colony due to trophyllaxis. Thus bait stations can be effective as part of an overall plan to reduce the number of termites in a given acre. But as a defense strategy for a particular dwelling, baits certainly cannot stand alone.
Other methods used for termite detection and/or control include U.S. Pat. No. 3,564,750, which includes a form of baited trap which when actuated, discharges an insecticide onto the termites. A frangible insecticide container is mounted in an enclosed chamber and a projectile is held under spring tension by a consumable trigger means. When the trigger means is consumed by termites, the projectile is released which then breaks the container to discharge the insecticide. Signal devices associated with the trap indicate that the structure has been attacked by termites. This signal means is actuated when the trigger is released interrupting an electrical signal. U.S. Pat. No. 3,624,953 relates to a termite control system which includes an insecticide dispensing pipe which is vertically disposed within a hole adjacent to a dwelling. The pipe has a low unperforated portion for receiving a liquid insecticide and an upper portion having perforations through which the insecticide is dispensed in vapor form. A sleeve is provided at the upper end of the hole for mounting the pipe with its outer surface spaced inwardly from the walls of the hole so that the insecticide in vapor form may permeate the soil surrounding the hole.
U.S. Pat. No. 3,858,346 relates to the control of subterranean termites by impregnating the exposed lower timbers of the building a termiticidally effective amount of hexachlorocyclopentadene dimer in a liquid organic solvent carrier. U.S. Pat. No. 3,940,870 relates to a method of treating soil for controlling termites and the like. The method involves dispensing a termite toxic insecticide into soil in an active available state. In addition, an initially unavailable insecticide which is enveloped in the container made from material which is attractive to and edible by termites is provided to release insecticide when the container or a part thereof is eaten by termites. An odoriferous material is provided along with the initially unavailable insecticide whose release will signal the presence of termites.
U.S. Pat. No. 5,094,028 relates to a termite blocking system which introduces a non-toxic, termite-repelling, hygroscopic material such as salt into the pathways of subterranean termites. U.S. Pat. No. 4,809,554 relates to an apparatus and method for detecting insects by detecting ultrasonic signals which are generated by mechanical disturbances in material upon which insects are feeding. U.S. Pat. No. 4,937,555 relates to a piezoelectric apparatus and process for detecting insects in agricultural commodities. An electrical signal is generated in response to vibration of a certain frequency caused in an agricultural commodity. U.S. Pat. No. 4,941,356 relates to a process for detecting insects in wood by comparing the behavior patterns to actual noise and vibration patterns detected in the wood substrate after extraneous noise is filtered out. U.S. Pat. No. 5,005,416 relates to insect detection using a pitfall probe trap having a vibration detector. U.S. Pat. No. 3,909,975 relates to a method of soil treatment where a network of interconnected rigid or collapsible perforated pumps were installed below ground such as before the erection of a wood containing structure and an inlet pipe extends from the network to an accessible point. A solution or emulsion of a termiticide is pumped under pressure through the inlet pipes to impregnate the ground underlying and around the structure.
U.S. Pat. Nos. 4,812,741 and U.S. Pat. No. 5,126,679 relate to moisture monitoring systems. U.S. Pat. No. 3,943,750 relates to a probe elector for subterranean gases. U.S. Pat. No. 3,753,581 relates to a microbiological detection apparatus useful for determining the growth of microorganisms. The system operates by measuring electrical conductivity changes in sealed cells having selected varieties of nutrient media inoculated with a sample containing expected microbial contamination.
It is also known by some pest control operators that a moisture detector can be used when inspecting the actual wood of a structure. The presence of moisture may be a sign of termites. In this case, the moisture detector only provides a reason to check further.
Another problem in termite control is the substantial lack of convenient and accurate diagnostic and quantification techniques. The commonly accepted laboratory method of documenting baiting efficiency is to use a triple mark, release and recapture system which statistically documents the reduction in termite populations. Unfortunately, this method is quite complex and beyond the capability of almost all professional pest control operators. It is both time and labor intensive and as such, is all but preclusive in terms of routine residential or commercial use.
Under this methodology, a simple wooden stake is driven into the ground. Once termite activity is detected on the wooden stake, a collection station is then installed adjacent to the attacked stake to collect termites for marking. Marking is accomplished by the use of a dye such as Nile blue or a fluorescent paint which is applied directly to the termites. The marked termites are again released and later recaptured at the capture stations. This process is repeated three times until a baseline population number is reached to the extent that the colony foraging territory has been established. A bait toxicant can then be introduced through one or more of the collection stations. This process is then continued after the introduction of the toxicant to determine the extent of population decrease as a function of the decrease in the recapturing of marked termites.
As will be readily appreciated, this is an inexact way of determining the efficacy of the toxicants and recording and documenting the resulting decrease in population. Of course, this method is currently accepted by the Environmental Protection Agency. However, until now, there really has been no alternative. In addition, checking the stake usually involves disturbing the stake as well as feeding termites. Termites are likely to leave the stake after such a disturbance and not return.
Therefore, there remains a need to provide better, more convenient, more technologically accessible methods and devices for controlling termite population and for determining the efficacy of various toxicants, baits and/or overall termite control strategies.
The methods and devices of the present invention allow for long term monitoring either on a continuous or discrete basis in a manner which is quick, efficient, and easy enough to allow use by all levels of the pest control industry.